1. Field of the Invention
This invention relates to the enzymatic treatment of the cellulose portion of corn hulls to convert a substantial portion thereof to glucose.
2. Description of the Prior Art
Cellulose is the earth's most abundant resource. The estimated annual accretion, including trees and annual plants, is on the order of 22 billion tons as compared to 100 million tons for corn starch. In contrast to oil and coal, cellulose is a directly renewable resource. The energy for its synthesis comes from the sun and its building blocks are derived from CO.sub.2 in the atmosphere.
Cellulose is a water-insoluble polymer of linearly linked .beta.-1,4 glucose residues and may be hydrolyzed to sugars. Intertwining of long cellulose chains into fibrils and fibers is involved in imparting crystallinity and insolubility to the polymer. Cellulose occurs naturally in perennial and annual plants as cell wall structural material and in fungi and even in certain bacteria. Sources which are generally considered to be of potential commercial importance for conversion of cellulose into sugars or other chemicals include the following:
Wood and lumbering by-products PA1 Pulp and paper wastes PA1 Industrial and municipal wastes PA1 Annual plant wastes PA1 Agricultural residues PA1 Food processing residues
The state of the art of cellulose conversion through mid-1974 was presented at an NSF-sponsored symposium entitled "Cellulose as a Chemical and Energy Resource," University of California at Berkeley, June 25-27, 1974. The proceedings were published as Symposium No. 5 of Biotechnology and Bioengineering, C. R. Wilke, Editor, published by John Wiley & Sons, Inc., New York, N. Y., 1975.
The state of the art through mid-1975 was presented at (1) the Eighth International Cellulose Conference, SUNY College of Environmental Science and Forestry, Syracuse, New York, May 19-23, 1975, and (2) Symposium on Enzymatic Conversion of Cellulose Materials: Technology and Applications, U.S. Army Natick Development Center, Natick, Mass. Sept. 8-10, 1975.
Particularly pertinent publications relating to the conversion of cellulose waste products to glucose are: Andren, Robert K. et al., "Production of Sugars from Waste Cellulose by Enzymatic Hydrolysis, Part I: Primary Evaluation of Substrates;" Presented at 8th Cellulose Conference, SUNY, Syracuse, NY, May 19-23, 1975, and Spano, L. A. et al., "Enzymatic Hydrolysis of Cellulose Wastes to Glucose," Publication from U.S. Army Natick Development Center, Sept. 8, 1975.